A circuit breaker of this type is shown diagrammatically in accompanying FIG. 1 which is a fragmentary view in axial half-section. Reference 1 designates a drive rod 1 connected to a tube 2 carrying a blast piston 3 provided with passages 3A and a blast nozzle 4. A blast volume 5 is defined by the tube 2 and a fixed tube 6 which is coaxial therewith and which is integral with a block 7 that is connected to a first terminal of the circuit breaker (not shown). Contacts 7A provide the electrical connection between the block 7 and the sliding tube 2.
Reference 8 designates the fixed arcing contact, which is tubular in shape and which is connected to a second terminal of the circuit breaker (not shown).
The second arcing contact, referenced 9, is also tubular and constitutes a semi-moving contact subjected to thrust by a first end of a spring 10 whose second end bears against a shoulder of the tube 2. When the circuit breaker is in the engaged position, as shown in FIG. 1, portions of the tubes 9 and 2 overlap. On circuit breaker disengagement, the tube 2 begins to move without entraining the contact 9, thereby precompressing the volume 5 before the end-to-end contacts 8, 9 separate which happens only when the annular ends 2A and 9A of the tubes 2 and 9, respectively come into contact. Contacts 9B allow current to pass between the tube 9 and the tube 2.
It can be seen that this circuit breaker includes a large number of electrical contacts. An object of the present invention is to provide a circuit breaker having end-to-end arcing contacts but with a small number of electrical contacts so as to reduce the price of the circuit breaker and its maintenance costs.